Formicoidea

Formicoidea can be distinguished from other superfamilies in Aculeata by the combination of a narrow, nodose petiole and metapleural glands. Within Hymenoptera, ants differ from their closest relatives (Vespidae, Apidae) by the presence of a distinct petiolar node, geniculate antennae, and the universal presence of wingless worker castes. The extinct family †@@@idae is distinguished from Formicidae by plesiomorphic characters retained from vespoid ancestors.

Formicoidea occupies nearly all terrestrial habitats worldwide except Antarctica, the Arctic, and extreme high-elevation tropical mountains. Ants occur in deserts, rainforests, grasslands, woodlands, and urban environments. Specific nesting substrates include soil, rotting wood, leaf litter, rocks, and vegetation. Some species inhabit specialized microhabitats such as myrmecophilous plant domatia or cultivate fungi in subterranean gardens.

Global distribution across all continents except Antarctica; absent from Arctic regions and isolated high-elevation tropical peaks. Highest diversity occurs in tropical regions, particularly Central and South America, Africa, and Southeast Asia. California alone harbors approximately 300 species.

Activity patterns vary by species and climate. Temperate species typically exhibit seasonal activity with winter dormancy; tropical species may be active year-round. Reproductive swarming (nuptial flights) occurs primarily in spring and summer in temperate regions, often triggered by warm, humid conditions following rain.

Complete metamorphosis with egg, larva, pupa, and adult stages. Colonies are perennial and may persist for years to decades. Development includes distinct castes: reproductive queens, reproductive males, and sterile workers. Queens are typically the sole egg-layers. Colony founding may occur through single queens (haplometrosis) or multiple queens (pleometrosis).

Eusocial behavior with cooperative brood care, overlapping generations, and reproductive division of labor. Communication occurs primarily through chemical signals (pheromones) and tactile cues. Trail pheromones mark foraging routes; alarm pheromones trigger defensive responses. Trophallaxis (mouth-to-mouth food exchange) serves nutritional and communicative functions. Some species exhibit complex behaviors including agriculture (fungus cultivation), animal husbandry (aphid tending), and slave-making.

Ants function as ecosystem engineers, predators, scavengers, seed dispersers, and soil modifiers. In tropical ecosystems, ants and termites may constitute up to one-third of total animal biomass. Formicoidea influences soil structure through nest excavation, participates in nutrient cycling, and regulates populations of other arthropods. Mutualistic relationships with plants (myrmecophytes) and hemipterans (tending for honeydew) are widespread.

Ants provide ecosystem services including pest control, soil aeration, and seed dispersal. Some species are economically significant pests: carpenter ants (Camponotus) damage wooden structures; invasive species such as Argentine ants (Linepithema humile) displace native fauna and disrupt ecosystems; fire ants (Solenopsis) inflict medically significant stings. Ants are extensively studied in behavioral ecology, sociobiology, and as model organisms for complex systems research.

• VespoideaWasps share the narrow waist and some eusocial species, but lack the nodose petiole, metapleural glands, and distinct worker caste of Formicoidea
• ApoideaBees share Hymenoptera features and some eusociality, but possess branched body hairs for pollen collection, lack the petiolar node, and do not have the same caste differentiation

Popular media frequently misrepresents ant biology: workers are exclusively female, not both sexes; colonies contain single reproductive queens rather than princesses marrying male workers; and ant diversity far exceeds the simplistic 'red ant/black ant' dichotomy. Wingless males have been repeatedly misidentified as new species or worker castes in taxonomic history.

• eusocial
• Hymenoptera
• Aculeata
• ecosystem engineers
• invasive species
• model organisms

• BugGuide
• iNaturalist taxon
• NCBI Taxonomy
• UC Davis Doctoral Candidate Brendon Boudinot: Adding to Our Knowledge of Ants | Bug Squad
• Bees Are Your Buddies; Ants Are Your Friends | Bug Squad
• Why Rodney Dangerfield Would Have Liked Male Ants--and Probably What Brendon Boudinot Is Doing | Bug Squad
• Ants: 'The Little Things That Run the World' | Bug Squad
• Big black ants in the home: Carpenter ants, Camponotus spp. — Bug of the Week
• The sweet smell of ants - Citronella or Large yellow ants, Acanthomyops interjectus — Bug of the Week
• THE GUILD OF SAPROBIONTIC NEMATODES ASSOCIATED WITH ANTS (FORMICOIDEA)
• Evolution and systematics of the Aculeata and kin (Hymenoptera), with emphasis on the ants (Formicoidea: †@@@idae fam. nov., Formicidae)